Move ::nPruneTarget into BlockManager

src/kernel/blockmanager_opts.h

@@ -0,0 +1,20 @@
+// Copyright (c) 2022 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_KERNEL_BLOCKMANAGER_OPTS_H
+#define BITCOIN_KERNEL_BLOCKMANAGER_OPTS_H
+
+namespace kernel {
+
+/**
+ * An options struct for `BlockManager`, more ergonomically referred to as
+ * `BlockManager::Options` due to the using-declaration in `BlockManager`.
+ */
+struct BlockManagerOpts {
+    uint64_t prune_target{0};
+};
+
+} // namespace kernel
+
+#endif // BITCOIN_KERNEL_BLOCKMANAGER_OPTS_H